Project Summary This application focuses on primary language impairment (PLI), defined as low language performance despite otherwise normal development. PLI occurs in 7% of the US population with similar rates presumed globally. Children with PLI are four times more likely to have a reading problem, often have trouble with social relationships, and have poorer long-term vocational outcomes. The proposed project will be the first to investigate PLI in Vietnamese children. Without a firm understanding of how PLI manifests in monolingual Vietnamese speakers, it is nearly impossible to identify and treat PLI in bilingual children in the US whose first language is Vietnamese. The lack of information on monolingual Vietnamese disorders drives my pursuit of the K23 award. I have excellent pre- and post-doctoral research training in child bilingualism, a clinical background in speech-language pathology, and I am fluent in Vietnamese. I need further training/mentorship in four areas: cross-linguistic PLI, literacy development and disorders, advanced statistical procedures, and international collaboration. My mentoring team: Dr. Catherine Snow of Harvard University (Primary mentor) is internationally recognized in literacy development and language-literacy relations; Dr. Margaret Friend (Co-mentor) of San Diego State University (SDSU) is conducting a multi-site R01 on language development and cross-linguistic comparisons; Dr. Sonja Pruitt-Lord (Consultant) of SDSU has expertise in preschool language impairment; Dr. Jillian Wiggins (Consultant) of SDSU has expertise in statistics and child development; Dr. Binh Ngo (Consultant) of Harvard University is a linguist and director of the Vietnamese Language Program; and Dr. Yen Nguyen (Consultant) of the Vietnam National Institute of Education Management is the co-founder of the Training and Development Center for Special Education (TDCSE). The proposed study will be conducted in Hanoi, the capital of Vietnam, in collaboration with TDCSE, the consortium site. The central hypothesis is that children with PLI will show subtle cognitive weaknesses underlying language impairment despite normal non- verbal intelligence, and language and cognitive skills in kindergarten will predict literacy outcomes in second grade. Aim 1 compares children with and without language impairment on a set of language and cognitive tasks to profile Vietnamese PLI. Aim 2 statistically models growth trajectories in reading (decoding and comprehension) for participants in kindergarten through second grade, and Aim 3 identifies language-cognitive skills in kindergarten that predict reading outcomes in second grade. Study findings will contribute to theories on cross-linguistic PLI and directly inform my work with bilingual children in the US. Collectively, the proposed training, mentorship and research activities address Aim 4, which is to develop into an independent, innovative researcher of PLI and literacy. Training includes (a) reduced teaching and service responsibilities, (b) mentorship from senior scientists in language-literacy development and disorders, (c) hands-on experience building an international, interdisciplinary team, and (d) preliminary data for an R01 application.